Liquid pump

ABSTRACT

A fluid pump, in particular a water pump, has a pump housing ( 11 ) that surrounds a pump wheel and a motor housing, connected to the pump housing, in which an electric motor ( 21 ) driving the pump wheel is received along with a stator ( 22 ) and rotor. For the sake of sealing off the pump from the escape of fluid and sealing off the motor housing from the penetration of fluid, with only one seal, and with assembly of the fluid pump without additional connecting elements, the pump housing ( 11 ) has a lower housing part ( 12 ) with an annular rib ( 14 ) protruding radially outward, and an upper housing part ( 13 ) slipped onto the lower housing part ( 12 ). Between the free annular face end of the upper housing part ( 13 ) and the annular rib ( 14 ), there is a sealing ring ( 15 ). The motor housing is embodied as a housing pot ( 26 ), which with a gripping edge ( 28 ) fits over the annular rib ( 14 ), sealing ring ( 15 ), and part of the upper housing part ( 13 ), and is locked to the upper housing part ( 13 ), producing an axial clamping force (FIG.  3 ).

PRIOR ART

[0001] The invention is based on a fluid pump, in particular a waterpump, as generically defined by the preamble to claim 1.

[0002] In such fluid pumps, there is a need to seal off the pump housingfrom the escape of fluid and to seal off the motor housing from thepenetration of fluid, such as splashing water, from the outside. To thatend, it is known, after the installation of the electric motor, to sealoff the motor housing in a manner proof against splashing water with ahousing cap, and to tightly cover the pump housing against the escape offluid by means of a cap flange and a sealing inlay. The pressure forcebetween the cap flange and the pump housing required for the tightconnection is achieved by screw connections, which are offset from oneanother by the same circumferential angles. The motor housing is securedto the cap flange, and the power takeoff shaft of the electric motor ispassed through the cap flange in a sealed fashion and in the interior ofthe pump housing receives the pump wheel in a manner fixed againstrelative rotation.

ADVANTAGES OF THE INVENTION

[0003] The fluid pump of the invention having the characteristics ofclaim 1 has the advantage that for sealing off the pump housing and themotor housing, only one seal is needed, and the contact-pressure forceagainst the seal is generated without additional fastening means. Asingle sealing ring takes on both functions, that is, sealing off thepump housing from the escape of fluid and sealing off the motor housingfrom the penetration of fluid from outside. The assembly and disassemblyof the pump are extremely simple and allow the costs for production andrepair to be dropped markedly. Since separate fastening means are notneeded, the logistics of the assembly line can be simplified and someassembly tools can be dispensed with, which further contributes tolowering the production costs of the pump.

[0004] By the provisions recited in the other claims, advantageousrefinements of and improvements to the pump defined by claim 1 arepossible.

[0005] In an advantageous embodiment of the invention, the stator of theelectric motor and the lower housing part of the pump housing are fixedagainst one another nonrotatably, and the upper housing part and thelower housing part are positioned correctly relative to one another andheld nonrotatably against one another. This connection between thestator and the inner part of the housing on the one hand and the lowerand upper parts of the housing on the other, preferably performed by atongue and groove connection, serves on the one hand to provide anassembly code and on the other forms a relative-rotation preventer uponassembly, which assures a correct association of the stator, motorhousing and pump housing.

[0006] In an advantageous embodiment of the invention, the lockingbetween the housing pot and the upper housing part of the pump housingis embodied like a bayonet mount, and on the upper housing part it hasprotruding retaining ribs, disposed equidistantly over the circumferenceof the upper housing part, and on the pot edge of the housing pot it hasundercuts, which can be brought into nonpositive and positive engagementwith one another by relative rotation of the housing pot and upperhousing part.

[0007] In an advantageous embodiment of the invention, an axiallyprotruding stop is disposed on the upper housing part, preferably on aretaining rib, and one of the undercuts strikes this stop at the end ofthe relative rotation, required for the locking, of the housing pot andthe pump housing. This limitation of the relative rotary motion betweenthe housing pot and the pump housing is important so that the motorhousing will always have a defined position relative to the stator, andlater installation of the triggering electronics for the motor on themotor housing can be accomplished without problems.

[0008] In an advantageous embodiment of the invention, arelative-rotation preventer, which is operative once the locking hasbeen established, is provided between the housing pot and the upperhousing part when the undercut contacts the stop of the upper housingpart, and which nonrotatably connects the housing pot and the pumphousing to one another. This relative-rotation preventer assures thateven in rough operation, the connection between the upper housing partand the housing pot will not come loose unintentionally.

[0009] In an advantageous embodiment of the invention, the pot bottom ofthe housing pot is provided with an oblong slot extending in thecircumferential direction, through which slot the winding terminals ofthe stator are passed. This oblong slot makes the relative rotationbetween the housing pot and the electric motor stator, which isconnected to the pump housing in a manner fixed against relativerotation, possible, which relative rotation is required for locking thehousing pot and the upper housing part of the pump housing. The oblongslot is covered by an electronics housing, in which the triggeringelectronics for the electric motor are integrated.

DRAWING

[0010] The invention is described in further detail in the ensuingdescription in terms of an exemplary embodiment shown in the drawing.Shown are:

[0011]FIG. 1, a perspective view of a water pump;

[0012]FIG. 2, a back view of the water pump, in the direction of arrowII in FIG. 1;

[0013]FIG. 3, the water pump of FIG. 1 with the housing pot partlyremoved;

[0014]FIG. 4, a perspective view of the lower housing part of the pumphousing with the pump wheel and the electric motor, driving the pumpwheel, of the water pump in FIG. 1;

[0015]FIG. 5, a detail showing a section taken along the line V-V inFIG. 1 with the locking between the pump housing and the housing pot notyet accomplished;

[0016]FIG. 6, a detail showing a section through the housing pot alongthe line VI-VI in FIG. 1, with the pump housing (not shown in section)locked to the housing pot.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0017] The water pump, shown in perspective in FIG. 1 as an exemplaryembodiment for a fluid pump in general, is preferably used in motorvehicle construction in the cooling loop of the internal combustionengine or in the heating loop of the heating system. It has a two-partpump housing 11, which is composed of a lower housing part 12 and anupper housing part 13 slipped onto the lower housing part. The lowerhousing part 12, on its periphery, has a radially outward-protrudingannular rib 14, which serves as a support for the annular face end ofthe upper housing part 13 and for a sealing ring 15 slipped onto thejacket of the lower housing part 12 and located between the annular rib14 and the face end of the upper housing part 13. An axial intake neck16 surrounding an inlet opening 161 and an outlet neck 17 surrounding anoutlet opening 171 and extending at a tangent away are formed onto theupper housing part 13. One spiral channel 181, 182 is formed in each ofthe two housing parts 12, 13. The two channels 181, 182, which restcongruently on one another once the upper housing part 13 has beenslipped onto the lower housing part 12 form a pressure spiral 18 (FIG.5) that discharges into the intake neck 16.

[0018] In FIG. 4, only the channel 181 of the pressure spiral 18embodied in the lower housing part 12 can be seen; it is covered by thechannel 182 of the pressure spiral 18 that is embodied identically inthe upper housing part 13, and the outlet neck 17 on the pressure sideis slipped over the edge of the orifice, which edge forms one half ofthe outlet opening 171, of the lower channel 181 of the pressure spiral18. A pump wheel 19 is disposed coaxially with the axis of the pumphousing 18 and is seated in a manner fixed against relative rotation ona power takeoff shaft 20 of an electric motor 21, which shaft protrudescoaxially into the pump housing 11. The rotating pump wheel 19 aspirateswater axially via the intake neck 16 and pumps it into the pressurespiral 18, from which the water flows out at pumping pressure via theoutlet neck 17.

[0019] The electric motor 21, in a known manner, comprises a stator 22(FIG. 4) and a rotor, not further shown here, which is surroundedannularly by the stator 22. The stator 22 has a stator winding 23, whichcan be supplied with current via winding terminals 24, 25 (FIG. 2). Theelectric motor 21 is received in a housing pot 26, which fits over theannular rib 14 on the lower housing part 12, the sealing ring 15, andpart of the upper housing part 13, and which is locked to the upperhousing part 13 upon the establishment of an axial clamping forcebetween the upper housing part 12 and the housing pot 26. To that end,an annular bracing shoulder 27 (FIG. 5) for the annular rib 14 on thelower housing part 12 and a gripping edge 28 axially protruding past thebracing shoulder 27 are embodied on the pot opening 261 of the housingpot 26; when the housing pot 26 is placed on the pump housing 11, thegripping edge, with its inside face 281, slides over the annular rib 14,sealing ring 15, and a peripheral portion of the upper housing part 13,until the annular rib 14 strikes the bracing shoulder 27.

[0020] The housing pot 26, in its pot bottom 262 (FIG. 2), has an oblongslot 29 extending in the circumferential direction, through which slotthe winding terminals 24, 25 of the stator winding 23 are passed.Although not otherwise shown here, an electronics housing is mounted onthe pot bottom 261 and covers the oblong slot 29 and contains thetriggering electronics, for instance for regulating the rotary speed,for the electric motor 21 that are to be connected to the windingterminals 24, 25.

[0021] As can be seen in FIGS. 1, 3, 5 and 6, the locking between thehousing pot 26 and the upper housing part 13 is embodied like a bayonetmount, and on the upper housing part 13, it has retaining ribs 30,disposed equidistantly over the circumference, and undercuts 31 that areembodied on the gripping edge 28. The retaining ribs 30 and undercuts 31are brought into engagement with one another by relative rotation of thehousing pot 26 and the upper housing part 13 of the pump housing 11, andas the relative rotation increases, an axial displacement motion ofthese two components ensues, which brings about a nonpositive pressingof the sealing ring 15 placed between the annular rib 14 and the faceend of the upper housing part 13.

[0022] The rotary motion is limited by a stop 32 (FIGS. 1 and 3), whichis embodied on one of the retaining ribs 30 and protrudes axially intothe path of rotation of the undercuts 31. The established locking of thehousing pot 26 and the upper housing part 13 of the pump housing 11 isassured by a relative-rotation preventer 33 (FIGS. 1, 3 and 6). Therelative-rotation preventer 33 has an axially elastically deformable rib34, which protrudes outward from the upper housing part 13 and isdisposed between two successive retaining ribs 30 in such a way that itis deflected elastically by one of the undercuts 31 when the housing pot36 is being slipped onto the upper housing part 13. Once this undercut31 has rotated to in front of the associated retaining rib 30, the rib34 springs back again and places itself against the circumferentiallypointing end edge of the undercut 31, so that reverse rotation of thehousing pot 26 is prevented. A disassembly from the pump housing 11 andhousing pot 26 can be accomplished, by a contrary relative rotarymotion, only whenever the elastic rib 34 is lifted, with an auxiliarytool, out of the path of rotation of the undercuts 31.

[0023] The assembly of the water pump is performed as follows:

[0024] The sealing ring 15 embodied as an O-ring is mounted on thepreassembled unit shown in FIG. 4, comprising the lower housing part 12,and the electric motor 21 with stator 22, rotor and power takeoff shaft20, and this is done by slipping the sealing ring onto the jacket of thelower housing part 12 with slight expansion, until it contacts theannular rib 14 of the lower housing part 12. As the sectional view inFIG. 5 shows, the stator 22 and the lower housing part 12 are securedagainst relative rotation to one another by a tongue and grooveconnection 35. This tongue and groove connection 35 simultaneouslyserves as an assembly code for the correct association in terms ofrotary position of the stator 22 and the lower housing part 12.

[0025] The upper housing part 13 is slipped (FIG. 3) over thepreassembled unit, including the sealing ring 15. The lower housing part12 and the upper housing part 13 are fixed nonrotatably against oneanother by a tongue and groove connection 36, which at the same timeserves as an assembly code for the correct positioning of the upperhousing part 13 and the lower housing part 12 in the process of slippingthe one onto the other. Of the tongue and groove connection 36, all thatcan be seen in FIG. 4 is the axially extending groove in the lowerhousing part 12.

[0026] After the pump housing 11 has been put together, the housing pot26 is slipped onto the stator 22 (FIG. 3), whereupon the gripping edge28 at the pot opening 261 increasingly fits over the annular rib 14,sealing ring 15 and upper housing part 13, and the undercuts 31 slidealong the gripping edge 28 between the retaining ribs 30 on the upperhousing part 13. In this process, the winding terminals 24, 25 of thestator winding 23 pass through the oblong slot 29. The process ofslipping the housing pot 26 on is concluded once the housing pot 27 andthe lower housing part 12 abut one another at the bracing shoulder 27.Now, by a rotary motion of the housing pot 26, the undercuts 31 arerotated to in front of the retaining ribs 30, the rotary motion beinglimited by the stop 32. After the rotary motion of the housing pot 26,the sealing ring 15 is axially compressed and reliably seals off notonly the pump housing 11 from the escape of water but also the housingpot 26 from the penetration of water. If one undercut 31 strikes thestop 32 in the rotary motion of the housing pot 26, then the rotarymotion of the housing pot 26 is blocked, and the rib 34, elasticallydeflected by an undercut 31, of the relative-rotation preventer 33 isreleased again by the undercut 31, so that the rib 34 springs back intoits original position and, by engaging the undercut 31 from behind,prevents a reverse rotation of the housing pot 26 in the circumferentialdirection (FIGS. 1 and 6).

[0027] A bayonet mount is distinguished by the fact that the retainingribs 30 and/or undercuts 31 have an axial depth that increases in thedirection of rotation, so that upon rotation of the two parts to bejoined together, an axial clamping force and thus a contact-pressureforce on the sealing ring 15 can be generated. Instead of being embodiedwith such a bayonet mount, the locking can be accomplished withretaining ribs and undercuts of the kind that have a constant axialwidth or thickness. In that case, the axial association of the retainingribs 30 on the upper housing part 13 and the undercuts 31 on the housingpot 26 must be done such that in the assembly process, before and duringthe rotation of the housing pot 26 and pump housing 11, a pressure forcethat compresses the sealing ring 15 must be brought to bear, so that theundercuts 31 on the housing pot 26 can be rotated to in front of theretaining ribs 30 on the upper housing part 13.

1. A fluid pump, in particular a water pump, having a pump housing (11)receiving a pump wheel (19) and having a motor housing connected to thepump housing (11), in which motor housing an electric motor (21) thatdrives the pump wheel (19) is received along with a stator (22) androtor, characterized in that the pump housing (11) has a lower housingpart (12), with an annular rib (14) protruding radially outward, and anupper housing part (13) thrust onto the lower housing part (12); thatbetween the free, annular face end of the upper housing part (13) andthe annular rib (14), a sealing ring (15) is disposed; and that themotor housing is embodied as a housing pot (26), which fits over theannular rib (14), the sealing ring (15), and part of the upper housingpart (13) and is locked to the upper housing part (13), exerting anaxial clamping force.
 2. The pump of claim 1, characterized in that anannular bracing shoulder (27) for the annular rib (14) on the lowerhousing part (12) and a gripping edge (28) protruding past the bracingshoulder (27) are embodied on the pot opening (161) of the housing pot(26), and the gripping edge slides with its inside face (281) past theannular rib (14), the sealing ring (15), and a portion of the upperhousing part (13).
 3. The pump of claim 1 or 2, characterized in thatthe stator (22) and the lower housing part (12) are positioned correctlyrelative to one another and fixed nonrotatably on one another,preferably via a positive-engagement connection (35):
 4. The pump of oneof claims 1-3, characterized in that the upper housing part (13) and thelower housing part (12) are positioned correctly relative to one anotherand fixed nonrotatably on one another, preferably via apositive-engagement connection (35).
 5. The pump of one of claims 1-4,characterized in that the locking between the housing pot (26) and theupper housing part (13) has retaining ribs (30), protruding from theupper housing part (13) and disposed equidistantly over thecircumference of the upper housing part (13), and undercuts (31),embodied on the gripping edge (28), which can be brought into engagementwith one another in the manner of a bayonet mount by means of relativerotation of the housing pot (26) and the upper housing part (13).
 6. Thepump of claim 5, characterized in that an axially protruding stop (32)is disposed on the upper housing part (13), preferably on the end of aretaining rib (30), and one of the undercuts (31) strikes this stop atthe gripping edge (28) at the end of the relative rotation, required forthe locking, of the housing pot (26) and the pump housing (11).
 7. Thepump of claim 5 or 6, characterized in that a relative-rotationpreventer (33), which is operative after the establishment of thelocking, is provided between the housing pot (26) and the upper housingpart (13).
 8. The pump of claim 7, characterized in that therelative-rotation preventer (33) has at least one axially elasticallydeformable rib (34), which protrudes from the upper housing part (13)and is disposed such that when the housing pot (26) is slipped onto theupper housing part (13), this rib can be deflected by an undercut (31)sliding through between the retaining ribs (30), and after rotation ofthe undercut (31), the rib springs back in front of the associatedretaining rib (30) and rests on the end face pointing in thecircumferential direction of the undercut (30).
 9. The pump of one ofclaims 1-8, characterized in that the stator (22) has winding terminals(24, 25) for electrical contacting of a stator winding (23), and thehousing pot (26) has an oblong slot (29), extending in thecircumferential direction in the pot bottom (262), through which slotthe winding terminals (24, 25) extend from the housing pot (26).
 10. Thepump of claim 9, characterized in that the oblong slot (29) has alength, measured in the circumferential direction, that is greater thanthe rotation travel of the housing pot (26) relative to the pump housing(11) connected to the stator (22) in a manner fixed against relativerotation.
 11. The pump of one of claims 1-10, characterized in that thepump housing (11) has an inlet opening (161) coaxial with the pump wheel(19) on the intake side and an outlet opening (171) tangential to thepump wheel (19) on the pressure side, in which outlet opening a pressurespiral (18) surrounding the pump wheel (19) discharges; and that thepressure spiral (18) is formed by two channels (181, 182), resting onone another, of which one is formed in the lower housing part (12) andone is formed in the upper housing part (13) of the pump housing (11).12. The pump of claim 11, characterized in that the inlet opening andoutlet opening (161, 171) are each surrounded by one of two connectionnecks (16, 17) formed integrally onto the upper housing part (13).